Rotary lithographic printing machine for direct or offset printing



C. L. STERN. ROTARY LITHOGRAPHIC PRINTING MACHINE FOR DIRECT 0R OFFSET PRINTING.

' 1 APPLICATION FILED 00?: 7. 1921.

1,423 1 65 P te ed July 18, 1922.

CARL LOUIS swarm, or

r pm" LONDON, ENGLAND, ASSIGNOR TO LINOTYPE AND MACHINERY LIMITED, 01 LONDON, ENGIJAND.

- Specification of Letters Patent; Pa te mted July 1S, 12,

Application filed October 7, 1921. Serial No. 506,024.

To all whom. it may concern:

Be it known that I, CARL LOUIS STERN, a citizen of the United States of America,

and residing at 9 Kingsway, London, England, have invented new and useful Improvements in Rotary Lithographic Printing Machines for Direct or Offset Printing, of which the following is the specification.

This invention relates -to rotary lithographic printing machines for direct or offset printing and has for its object to provide a machine which can be used for printing (a) single side direct, (b) single side offset, (a) perfector offset, and (03) two colour offset.

Various arangements of cylinders, plate surfaces thereon and inking mechanisms working in conjunction the ewith, have heretofore been proposed wit 1 the object of producing different variations of printing in one and the same machine. For ina stance, by the use of two directly co-acting plate surfaces on each of two cylinders, and inking'and damping mechanisms for either one or two plates on one of such cylinders, it has been proposed to produce single side offset, two-colour offset and perfector offset printing. Further, by the provision of a plurality of plate surfaces, together with appropriate colour-inking mechanisms on one cylinder, and a plurality of plate surfaces together with a single colour inking mechanism on another cylinder, .in conjunction with an intermediate transfer cylinder for offsetting to a single plate on the second cylinder impressions from all the plates on the first cylinder, it has been proposed to produce successive single side direct and multicolour. offset impressions. None of these arrangements, however, has afforded facilities for the continuous production of any desired one of all the above-named four variations of printing, and have involved, in one operation or another, double offsetting which gives rise to excessive consumption of ink and lack of uniformity in results.

According to the present invention the several variations referred toare rendered possible, without resorting to double offsetting, in a machine having two plate cylinders both of the same diameter, an impres-' "sion cylinder of half that diameter, two

plate surfaces on each plate cylinder adapted to co-act directly with the corresponding plate surfaces of the other plate cylinder, and mechanisms adapted tov damp and ink with respectively different colours two plates on one of said cylinders, by providing, in connection with the other of said cylinders, mechanisms for damping and inking a single plate thereon; by adapting one of the plate surfaces on that cylinder to be clothed with either a printing plate or an offset blanket; by adapting t e impression cylinder to be clothed with either va hard impression blanket or a rubber offset blanket; and by rendering the respective damping and inking mechanisms operable independently or conjointly in the manner hereinafter described. The invention will be described with ref erence to the accompanying drawing which shows diagrammatically in side elevation an arrangement of cylinders and damping and inking mechanisms according to the present invention. Q

Referring to the said drawing, 1 and 2 are the plate cylinders and 3 the impression cylinder, the cylinders 1 and 2 being of the same diameter and'having their axes referably both in the same horizontal p ane, and the cylinder 3 being of half the diameter of the plate cylinder and preferably located directly over the plate cylinder 1.-

4 and 5 are the plate surfaces of the plate cylinder 1, the surface 4 being adapted to receive either a printing plate or a rubber offset blanket and the surface 5 being adapted toreceive a rubber offset blanket. The corresponding plate surfaces 6 and 7 of the plate cylinder 2 are each adapted to receive' a printing plate.

The impression surface 14 of the impression cylinder 3 is adapted to be clothed either with a hard impression surface or with a rubber offset blanket.

According to the present invention, the

' cylinder 1 is provided with a single damping mechanism 8 and inking mechanism .9, which are preferably arranged thereon with sufficient space between'the respective rollers of these mechanisms to. enablethe pressman to readily inspect the pri'ntin condition and. results, and areiprovide" with suitable. trip-mechanism of known construction to enable them to damp and ink a single plate carried by the plate surface 4, or to be tripped out of actionas desired.

The plate cylinder 2 in the constructional form illustrated is provided with damping mechanism 10 coacting with an inking mechanism 11 for inking one plate with one colour and a second damping mechanism 12 coacting with a second inking mechanism 13 for the purpose of inking a second plate with another colour. The damping mechanisms are preferably located, as shown, near the upper part of the cylinder 2, but if desired, one of such mechanisms may be located at that part of the cylinder between the two inking mechanisms. Further, a single damping mechanism may be conveniently utilized for damping both plates. These damping and inking mechanisms for the plate cylinder 2 are provided with suitable tripping means whereby they may be operated either conjointly for inking two plates with respectively different colours or independently for inking one plate with a single colour. 1

It is to be understood that the trip ing mechanism for the damping and in ing mechanisms above referred to constitutes in itself no part of the present invention and may be of any known construction. Moreover, mechanism for tripping the respective cylinders out of contact with each other at the required stages of their operation of any known construction may be provided, as well as means whereby the impression cylinder gri; pers may be opened either once at ever rotation .or once at every alternate rotation of the said cylinder.

Owing .to the fact that in certain arrangements, according to the present invention, the so-called plate surfaces .are employed for-supporting a rubber offset blanket instead of a printing plate, it must be explain ed that the term plate surface is herein employed to designate that portion of the respective cylinder whereon either a printing plate or an offset blanket may be supported.

The methods of. operating the machine according to the present invention for the several variations of printing above referred to are as follows pression is thus'made from the plate on the' cylinder 1 on to the paper as it is passed between that cylinder and the. impression cylinder 3 above it. Durinvthis operation, of course, the damping an inking mechanisms appertaining to the plate cylinder 2 are not required, and are consequently rendered inoperative. Y

(b) For single side, offset printing, the impression surface 14 is furnished with a hard impression blanket, the plate surface 5 is clothed with a rubber offset blanket, and the plate surface 4 is left unclothed, while the damping and inking mechanisms 8 and 9 are tripped out of action. The plate surface 7 of the cylinder 2 is provided with a printing surface, and the first colour inking and damping mechanisms 10 and 11 are brought into action, while the second colour dampers and inkers 12, 13 are tripped and the respective plate surface 6 left unclothed.

are rendered operative to ink the plate on,

the plate surface 4. The plate surface 7 on the cylinder 2 is clothed with a printing plate, and the appropriate damping and inking mechanisms are rendered operative the.

plate surface 6 being left unclothed and they respective damping and inking mechanisms tripped out of action. The impression surface 14- is clothed with a rubber offset blanket. B this arrangement the impression from t e plate on the surface 4 is received on the offset blanket on the cylinder 3 and transferred thereby to one side of the paper and the impression received by the offset blanket on the surface 5 from the plate on the cylinder 2 is transferred by that offset blanket to the op osite side of the paperi passing between t e two cylinders 3 an (d) Two-colour offset printing may be effected with the impression surface 14 clothed with a hard impression blanket, both plate surfaces on the cylinder 1 being clothed with a rubber offset blanket, and with two plates on the cylinder 2 and both the inking and damping mechanisms appertaining to'that cylinder operative. The impressions in dif ferent colours received from the plates on cylinder 2 by the respective offset blankets on cylinder 1 are by this arrangement superimposed by this offsetfiblanket u on the.

paper passing between the two cylinders 1 measles during alternate rotations of the said cylinder.

Having described m invention, I declare that what I claim an desire to secure by Letters Patent is 1. In a rotary. lithographic printing machine, the combination with two plate cylinders both of the same diameter, an impression cylinder 'of half that diameter, two plate-carrying surfaces on each late cylinder adapted to co-act directly with the corresponding plate-carrying surfaces. of the other late cylinder and mechanisms adapted to amp and ink with respectively different colours two plates on one of said cylinders, of mechanisms adapted to damp and ink a single plate on the other of said cylinders.

2. In a rotary lithographic printing ma-.

' chine, the combmation with two directly ooacting plate cylinders both of the same 'di-- ameter and an impression cylinder of half that diameter adapted to oo-act directly with one of said plate cylinders, of two plate-carrying surfaces on the other of said plate cylinders, mechanisms adapted to damp and ink plates thereon with respectively di ferent colours, two' late-carryin r surfaces on the first plate cy inder one 0 which is adapted to carry either a printing plate or a rubber ofi'set blanket, mechanisms adapted to damp andink a single plate on said first plate cylinder, and .an' impression surface on the impression cylinder adapted to carry either a hard impression blanket or a rubber offset blanket.

lithographic printing ma-- .3. In a rotar bination with two directly chine, the com co-acting plate cylinders both-of the same diameter and an impression cylinder of half that diameter adapted to co-act directly with one of said plate cylinders, of two plate-carrying surfaces on the other of said plate cylinders, mechanisms adapted to dam and ink platesthereon'with respectively ifferent colours, two plate-carrying surfaces on the first plate cylinder one of which is adapted to carry either a printing plate or a rubber offsetblanket, mechanisms adapted ameter and an impression cylinder of half that diameter adapted to co-act directly with one of said plate cylinders, of two platecarrying surfaces on the other of said plate cylinders, independently operable mechanisms adapted to damp and ink two plates thereon with respectively different colours, two plate-carrying surfaces on the first plate cylinder one of which is adapted to carry either a printing plate or a rubber offset blanket, mechanisms ada ted to dam and ink a single plate on said rst platecylmder,

and an impression surfacelon the impression cylinder adapted to carry either a hard impression blanket or a rubber ofi'set blanket.

5. In a rotary lithographic pr'intin machine, the combination 'with two direct y 06- acting plate .cylinders both of the same diameter and an impression cylinder of half that diameter adapted to co-act directly with one of said late cylinders, .of two platecarrying sur aces on the other ofsaid plate cylinders, independently operable mechanisms adapted to damp and ink two lates thereon withrespe'ctively different co ours, twoplate-carrying surfaces on the first plate cylinder one of which is adapted to carry either a printin plate or a rubber offset blanket, mechanisms adapted to dam ink a single late on said first plate cylinder operable in ependently of the two-platedamping and inking mechanisms of the other cylinder, and an impression surface on the impression cylinder adapted to carry and either a'hard impression blanket or a rub- In testimony whereof I have 'afiixed my 

